_ by his words,all the audience clapped now and then until his lecture came to an end.

问题描述:

_ by his words,all the audience clapped now and then until his lecture came to an end.
A.Impressed B.To be impressed
选哪个?为什么?说一下具体原因

选A,表示听众被他的话感动了而鼓掌,
B是不定式,表示目的,意义变为了观众为了被感动,与常理不服.
此题如仍有疑问,欢迎追问!